System, Apparatus and Method for Enabling/Disabling Display Data Channel Access to Enable/Disable High-Bandwidth Digital Content Protection

ABSTRACT

A switcher device comprises a multiplexer coupled in-between at least one input and output cards. The multiplexer detects the presence of an event signal from an activated sink. In response to the detection of the event signal, the switch dynamically switches to a closed position in order to enable the at least one source to authenticate with the input card and the output card to authenticate with the at least one sink for security protocol encryption. In response to the non-detection of the event signal, the switch switches dynamically to an open position in order to disable the at least one source from authenticating with the input card, therefore the output card also does not attempt to authenticate with the at least one sink for security protocol encryption.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates generally to High-Bandwidth DigitalContent Protection. More particularly, the invention relates a method,apparatus, and system for enabling and/or disabling Display Data Channel(DDC) access to enable and/or disable High-Bandwidth Digital ContentProtection.

2. Background Art

As the digital distribution of television, movies, and music expands,content providers are growing increasingly concerned about thesimplicity with which content pirates can copy and share copy protectedmaterial. Various digital rights management (DRM) schemes have beendeveloped to ensure that television shows, movies, and music can only beviewed by authorized parties (i.e., paying consumers). The ContentScrambling System (CSS) used to encrypt DVDs and Apple's Fairplaytechnology are two widely-known examples of DRM schemes. One DRM schemeto protect digital content as it is transmitted over cables betweendevices is known as High-Bandwidth Digital Content Protection (HDCP).HDCP is a specified method developed by Digital Content Protection,L.L.C., for protecting copyrighted digital content as it travels acrossconnection interfaces and protocols such as DisplayPort (DP), DigitalVideo Interface (DVI), High-Definition Multimedia Interface (HDMI),Giga-bit Video Interface (GVIF), Digital Light Interface (DLI), UnifiedDisplay Interface (UDI), Internet Protocol (IP), Wireless Home DigitalInterface (WHDI), Transmission Control Protocol/Internet Protocol(TCP/IP), and Universal Serial Bus (USB). The HDMI specification definesan interface for carrying digital audiovisual content from a source suchas a DVD player, to a sink or display device such as a television (TV).As designed by the Digital Content Protection, L.L.C., when the sourceand sink/display are HDCP compliant, HDCP protected content is displayedbut the HDCP protected content cannot be copied and shared. When thesource is HDCP compliant and the sink/display is not HDCP compliant, thecopy protected material cannot be displayed, copied and/or shared. Whenthe source is HDCP compliant and the sink/display is not HDCP compliant,a non-copy protected material can be displayed, copied and/or shared.

HDCP is designed to prevent copying and sharing of copy protectedmaterial. There are issues with interoperability when the materialitself is non-copy protected. For example, when an HDCP compliant sourcesuch as a laptop is connected to an HDCP compliant sink/display device,non-HDCP protected content cannot, for example, be copied, shared, andreplayed at a later time even though the non-HDCP protected content canbe displayed on the sink/display device. Many HDCP compliant sources,such as laptops, choose to enable/disable content encryption based onthe downstream display's HDCP capabilities. These devices do not “care”if the real-time video content is actually copy protected or non-copyprotected and will leave content encryption enabled as soon as thedevice sees an HDCP compliant sink/display. In the academic field, forexample, a university instructor may want students to copy and sharecontent material that is not copy protected (e.g., the professor'sPowerPoint presentation). Even though the content is non-copy protected,the students will not be able to copy, replay or share the contentbecause the source and sink/display devices are HDCP compliant.

Accordingly, it is the object of the present invention to correctinteroperability issues related to HDCP. The present invention providesa system, apparatus, and method for enabling/disabling Display DataChannel access to enable/disable HDCP.

SUMMARY OF THE INVENTION

It is to be understood that both the general and detailed descriptionsthat follow are exemplary and explanatory only and are not restrictiveof the invention.

DISCLOSURE OF INVENTION

Principles of the invention provide a system, apparatus, and method forenabling/disabling Display Data Channel access to enable/disable asecurity protocol, such as HDCP. For example, in a first aspect of theinvention, a system for enabling/disabling Display Data Channel (DDC)access to enable/disable a security protocol comprises at least onesource, at least one sink, and a switcher device communicatively coupledin-between the at least one source and the at least one sink. Theswitcher device comprises a multiplexer coupled in-between at least oneinput and output cards and configured to transmit an audiovisual signalfrom the at least one input card to a first and at least a second outputcard via a physical connection. The multiplexer is configured todynamically switch between the first and at least second output cardbased on a user control signal that activates one of the at least onesinks. Each of the output cards is coupled to the at least one sink. Theinput card comprises an integrated circuit that includes a securityprotocol enabled receiver and a switch coupled in-between the securityprotocol enabled receiver and an Extended Display Identification Data(EDID) memory. The input card is configured to detect the presence of anevent signal from at least one user interfaced device. In response tothe detection of the event signal, the switch dynamically switches to aclosed position in order to enable the at least one source toauthenticate with the input card and the output card to authenticatewith the at least one sink for security protocol encryption. In responseto the non-detection of the event signal, the switch switchesdynamically to an open position in order to disable the at least onesource from authenticating with the input card, therefore the outputcard also does not attempt to authenticate with the at least one sinkfor security protocol encryption.

In a second aspect of the invention, a switcher device comprises amultiplexer coupled in-between at least one input and output cards andconfigured to transmit an audiovisual data signal from the at least oneinput card to a first and at least a second output card. The multiplexeris configured to dynamically switch between the first and at leastsecond output card based on a user control signal that activates one ofat least one sinks. Each of the output cards is coupled to the at leastone sink. The input card comprises an integrated circuit that includes aHigh-Bandwidth Digital Content Protection (HDCP) enabled receiver and aswitch coupled in-between the HDCP enabled receiver and an ExtendedDisplay Identification Data (EDID) memory. The at least one input cardis configured to detect the presence of an event signal from the atleast one user interface device. In response to the detection of theevent signal, the switch is configured to dynamically switch to a closedposition in order to enable the at least one source configured toauthenticate with the input card and the output card configured toauthenticate with the at least one sink for security protocolencryption. In response to the non-detection of the event signal, theswitch is configured to dynamically switch to an open position in orderto disable the at least one source from initiating an authenticationwith the input card, therefore the output card also does not attempt toinitiate an authentication with the at least one sink for securityprotocol encryption.

In a third aspect of the invention, a method for enabling/disablingDisplay Data Channel (DDC) access to enable/disable High-BandwidthDigital Content Protection comprises detecting a user control signal toactivate one of at least one sinks. The method further comprises inresponse to the detection of the user control signal, enabling theselected at least one sink for receiving audiovisual signal anddetecting an event signal. In response to the detection of the eventsignal, switching the switch dynamically to a closed position forenabling the at least one source to authenticate with the input card andenabling the output card to authenticate with the at least one sink forsecurity protocol encryption. The method further comprises permittingthe transmission of audiovisual signal from the at least one source tothe enabled at least one sink upon successful authentication anddisabling control of the enabled at least one sink from being able torecord since the audiovisual signal contains copy protected content. Inresponse to the non-detection of the event signal, switching the switchdynamically to an open position in order to disable the at least onesource from initiating an authentication with the input card, thereforethe output card also does not attempt to initiate an authentication withthe at least one sink for security protocol encryption. The methodfurther comprises permitting the transmission of the audiovisual signalto be displayed from the at least one source to the enabled at least onesink, and enabling control of the enabled at least one sink from beingable to be recorded since the audiovisual signal contains non-copyprotected content.

In a fourth aspect of the invention, an integrated circuit comprises anenabled High-Bandwidth Digital Content Protection (HDCP) receiver, anExtended Display Identification Data (EDID) memory, and a switch coupledin-between the security protocol enabled receiver and the EDID memory.The integrated circuit is configured to detect the presence of an eventsignal from at least one user interface device. In response to thedetection of the event signal, the switch is configured to dynamicallyswitch to a closed position in order to enable the at least one sourceconfigured to authenticate with the input card and the output cardconfigured to authenticate with the at least one sink for securityprotocol encryption. In response to the non-detection of the eventsignal, the switch is configured to dynamically switch to an openposition in order to disable the at least one source from initiating anauthentication with the input card, therefore the output card also doesnot attempt to initiate an authentication with the at least one sink forsecurity protocol encryption

In a fifth aspect of the invention, a computer program product forenabling and disabling a security protocol, the computer program productcomprises a computer readable storage medium having computer readableprogram code embodied therewith. The computer readable program codecomprises computer readable program code configured to: detect a usercontrol signal to activate one of at least one sinks; in response to thedetection of the user control signal, enabling the selected at least onesink for receiving audiovisual signal; detect an event signal; whereinin response to the detection of the event signal, switching the switcherdynamically to a closed position for enabling the at least one source toauthenticate with the input card and enabling the output card toauthenticate with the at least one sink for security protocolencryption; permit the transmission of audiovisual signal from the atleast one source to the enabled at least one sink upon successfulauthentication; and disable control of the enabled at least one sinkfrom being able to be recorded since the audiovisual signal containscopy protected content; wherein in response to the non-detection of theevent signal, switch the switch dynamically to an open position in orderto disable the at least one source from initiating an authenticationwith the input card, therefore the output card also does not attempt toinitiate an authentication with the at least one sink for securityprotocol encryption; permit the transmission of the audiovisual signalto be displayed from the at least one source to the enabled at least onesink; and enable control of the enabled at least one sink from beingable to record since the audiovisual signal contains non-copy protectedcontent.

The present invention seeks to overcome or at least ameliorate one ormore of several problems, including but not limited to: the ability toview, copy, and share non-copy protected content on source andsink/display devices that are HDCP compliant.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 is a schematic of a system in accordance with an illustrativeembodiment of the present invention.

FIG. 2 is a schematic of a system in accordance with an illustrativeembodiment of the present invention.

FIG. 3 is a schematic of system in accordance with an illustrativeembodiment of the present invention.

FIG. 4 is a schematic of an input card 308 in accordance with anillustrative embodiment of the present invention.

FIG. 5 is a schematic of an input card 508 in accordance with anotherillustrative embodiment of the present invention.

FIG. 6 is a schematic of an input card 608 in accordance with yetanother illustrative embodiment of the present invention.

FIG. 7 is a schematic of an input card 708 in accordance with yetanother illustrative embodiment of the present invention.

FIG. 8 illustrates a flowchart for enabling/disabling HDCP contentprotection in accordance with an illustrative embodiment of the presentinvention.

The foregoing will be apparent from the following more particulardescription of example embodiments of the invention, as illustrated inthe accompanying drawings in which like reference characters refer tothe same parts throughout the different views. The drawings are notnecessarily to scale, emphasis instead being placed upon illustratingembodiments of the present invention.

LIST OF REFERENCE NUMBERS FOR THE MAJOR ELEMENTS IN THE DRAWING

The following is a list of the major elements in the drawings innumerical order.

-   -   100 High-Bandwidth Digital Content Protection system    -   102 Collectively interface cable, link or physical connection of        102 a, 102 b    -   104 Collectively the source of 104 a, 104 b, . . . , 104 n    -   106 Collectively the sink/display of 106 a, 106 b, . . . , 106 n    -   108 Secret device keys    -   200 High-Bandwidth Digital Content Protection system    -   202 HDCP content or audiovisual data    -   210 Control function    -   212, 215 HDCP transmitter    -   214, 216, 514, 614, 714 HDCP receiver    -   219 Repeater    -   220 Central Processing Unit    -   300 System for enabling and disabling DDC    -   302 Switcher    -   304 Event signal    -   306 Multiplexer    -   308 Collectively the input card of 308 a, 308 b, . . . , 308 n    -   310 Collectively the output card of 310 a, 310 b, . . . , 310 n    -   316 User control signal    -   318 Processing unit    -   320 Transceiver    -   322 Control system    -   323 User interface device, specifically wireless/mobile device    -   324 User interface device    -   326, 526, 626, 726 Integrated circuit    -   328 Software Tools    -   330 Extended Display Identification Data    -   332, 532, 632 Switch    -   508, 608, 708 Input card    -   530 Internal EDID    -   535 External EDID    -   630, 730 EDID    -   800 Method for enabling/disabling DDC    -   805 Step—starts    -   810 Step of detecting a user control signal    -   815 Step of enabling the activated at least one sink    -   820 Step of detecting an event signal    -   825 Step of dynamically switching to an open position    -   830 Step of permitting the transmission of AV signal    -   835 Step of enabling the AV signal from being able to be        recorded and shared    -   850 Step of dynamically switching to a closed position    -   855 Step of permitting the transmission of audiovisual signal to        be viewed    -   860 Step of disabling the audiovisual signal from being able to        be recorded and shared

DETAILED DESCRIPTION OF THE INVENTION Mode(s) for Carrying Out theInvention Disclosure of Invention Definitions

Authorized device—An HDCP device that is permitted access to HDCPcontent. An HDCP transmitter may test if an attached HDCP receiver is anauthorized device by successfully completing the first and, whenapplicable, second part of the authentication protocol. If theauthentication protocol successfully results in establishingauthentication, then the other device is considered by the HDCPtransmitter to be an authorized device.

Downstream—Used as an adjective to refer to being towards thesink/display of the HDCP content stream.

DVI—Digital Video (or Visual) Interface, a digital interface standardcreated by the Digital Display Working Group (DDWG) to accommodate bothanalog and digital monitors.

Event Signal—A signal that includes, but not limited to, activating aparticular mode of a source.

HDCP—High-Bandwidth Digital Content Protection.

HDCP content—Audiovisual content that is protected by the HDCP system.HDCP content includes the audiovisual content in encrypted form as it istransferred from an HDCP transmitter to an HDCP receiver over anHDCP-protected Interface.

HDCP device—Any device that contains one or more HDCP-protectedinterface ports and is designed in adherence to HDCP.

HDCP Encryption—The encryption technology of HDCP when applied to theprotection of HDCP content in an HDCP system.

HDCP-protected Interface—An interface for which HDCP applies.

HDCP-protected Interface Port—A connection point on an HDCP Device thatsupports an HDCP-protected Interface.

HDCP receiver—An HDCP device that can receive and decrypt HDCP contentthrough one or more of its HDCP-protected interface ports.

HDCP repeater—An HDCP device that can receive and decrypt HDCP contentthrough one or more of its HDCP-protected interface ports, and can alsore-encrypt and emit the HDCP content through one or more of itsHDCP-protected interface ports. An HDCP repeater may also be referred toas either an HDCP receiver or an HDCP transmitter when referring toeither the upstream side or the downstream side, respectively.

HDCP transmitter—An HDCP device that can encrypt and emit HDCP contentthrough one or more of its HDCP-protected interface ports.

HDMI—Short for High-Definition Multimedia Interface, anindustry-supported, uncompressed, all-digital audio/video interface.

Mode—The mode of the source includes, but not limited to, playing ablu-ray DVD, displaying a PowerPoint presentation, displaying a website,collaborating on a white board application, using a document camera, andstreaming content from a media player.

Upstream—Term used as an adjective to refer to being towards the sourceof the HDCP content stream. The antonym of “downstream,” defined above.

FIGS. 1 and 2 illustrate examples of High-Bandwidth Digital ContentProtection (HDCP) systems 100, 200. Referring to FIG. 1, the HDCP system100 encrypts the digital content transmission between a video source 104(set-top box, computer, DVD, etc.) and a sink or display 106 (LiquidCrystal Display, television, etc.) via an interface 102 such as DigitalVideo Interface (DVI), High-Definition Multimedia Interface (HDMI), andDisplayPort.

FIG. 2 illustrates an HDCP system 200 wherein two or more HDCP devices104, 106 are interconnected through at least one interface 102 a, 102 b(collectively 102) such as HDCP-protected interface. A singlepoint-to-point HDCP link can involve one HDCP transmitter 212, and oneHDCP receiver 214. As such, a repeater 219 must decrypt the HDCP content202 at the HDCP receiver 214 on each of its inputs. The repeater 219must then re-encrypt the data with an HDCP transmitter 215 of each ofits outputs. The repeater 219 must inform the upstream device of itsdownstream connection, but it is the repeater's 219 responsibility tomaintain those connections. The audiovisual content protected by HDCP,HDCP content 202, flows from an upstream content control function 210into the HDCP system 200 at the most upstream transmitter 212. Fromthere, the HDCP content 202, encrypted by the HDCP system 200, flowsthrough a tree-shaped topology of HDCP receivers 214 over HDCP-protectedinterfaces 102 a. HDCP receivers 214 may be HDCP repeaters 219 thatserve as downstream HDCP transmitters 215 emitting the HDCP content 202further downstream to one or more additional HDCP receivers 216. Thesystem 200 is meant to stop HDCP-encrypted content from being played ondevices that do not support HDCP or which have been modified to copyHDCP content 202. Before sending data, the each transmitter 212, 215checks that the HDCP receivers 214, 216 are authorized to receive theHDCP content 202. If so, the transmitter 212 encrypts the HDCP content202 to prevent eavesdropping as it flows to the receiver 216. A centralprocessing unit 220 includes firmware to process the data 202 and otherinformation and control. The HDCP receiver 216 may incorporate a lecturesystem that permits non-copy protected content to be recorded. Forexample, such a lecture system may be a CAPTURELIVEHD system availablefrom Crestron Electronics, Inc. of Rockleigh, N.J. The system enables asimple and efficient end-to-end solution for recording, scheduling,processing, online distribution, and remote viewing of lecture andpresentation content. The recorded lecture system may include contentand microphone audio, plus full screen, picture-in-picture (PIP) andpicture-by-picture video, including from the instructor camera and anyother presentation source such as a PowerPoint®, DVD or website. Inanother embodiment, the lecture system may be a separate system thatconnects to the receiver 216 and the sink 106.

There are three facets of the content protection system. First, there isthe authentication protocol, through which the HDCP transmitter 212verifies that a given HDCP receiver 216 is licensed to receive HDCPcontent 202. Second, the legitimacy of the HDCP receiver 216 determined,encrypted HDCP content 202 is transmitted between the two devices 104,106 based on shared secrets established during the authenticationprotocol. The use of such shared secrets prevents eavesdropping devicesfrom utilizing the content. Finally, in the event that legitimatedevices are compromised to permit unauthorized use of HDCP content 202,renewability allows an HDCP transmitter 212 to identify such compromiseddevices and prevent the transmission of HDCP content 202.

The HDCP authentication protocol is an exchange between an HDCPtransmitter 212 and an HDCP receiver 216 that affirms to the HDCPtransmitter 212 that the HDCP receiver 214 is authorized to receive HDCPcontent 202. That affirmation is in the form of the HDCP receiver 216demonstrating knowledge of a set of secret device keys 108 (FIG. 1).Each HDCP device is provided with a unique set of secret device keys,referred to as the Device Private Keys, from Digital Content Protection,LLC. (DCP). The communication exchange, which allows for the receiver216 to demonstrate knowledge of such secret device keys 108, alsoprovides for both HDCP devices 104, 106 to generate a shared secretvalue that cannot be determined by eavesdropping on that exchange. Byhaving that shared secret information embedded into the demonstration ofauthorization, the shared secret can then be used as a symmetric key toencrypt HDCP content 202 intended only for the authorized device. Thus,a communication path is established between the HDCP transmitter 212 andHDCP receiver 216 that only authorized devices can access.

Device manufacturers typically purchase HDCP chips from a DCP-licensedsilicon vendor. These chips usually also provide Transition MinimizedDifferential Signaling (TMDS) encoders or decoders and otherHDMI-specific features. Every transmitter 212 will have at least oneHDCP transmitter chip and every receiver 216 will have at least one HDCPreceiver chip. The HDCP transmitters 212, and receivers 216 frequentlyrequire a microprocessor to implement the authentication state machines.Transmitters 212, 215 are HDMI transmitters.

To support HDCP, each transmitter 212 and receiver 216 must possess thefollowing elements:

Keys: Each HDCP transmitter 212, 215 and receiver 214, 216 has fortyunique 56-bit private keys. These keys are provided by DCP to licensedHDCP chip vendors, who pre-load the keys onto the chips before sellingthem to device manufacturers. These keys must never leave the chip andmay not be read by any other device.

KSVs: Each HDCP chip also has a public 40-bit value known as the KeySelection Vector (KSV). Each KSV consists of twenty binary 1s and twentybinary 0s. The KSVs and keys of all licensed HDCP devices aremathematically related according to a cryptographic key exchangeprotocol similar to Blom's scheme. In this scheme, any two licenseddevices can swap KSVs and use them, along with their private keys, tocome up with a shared secret key. This shared key can be used to encryptand decrypt the TMDS stream. The KSV can also be used to uniquelyidentify a transmitter or receiver.

HDCP cipher: Each chip must implement the HDCP cipher. The cipheraccepts a seed value and uses it to generate a deterministicpseudo-random stream of data. All HDCP cipher implementations shouldgenerate the same output stream given the same seed value. This publiclydefined cipher is used during both authentication and encryption.

Registers: Each HDCP receiver 214, 216 provides a series of pre-definedDigital Display Channel (DDC) accessible registers. All of the HDCPcommunications between the source 104 and sink/display 106 occurs by thesource 104 reading from and writing to these registers.

The Authentication and Encryption Protocols

HDCP authentication consists of three parts:

Part 1: The source 104 authenticates with the sink/display 106 connectedto its output. If successful, encryption is enabled and audiovisual(A/V) content transmission begins.

Part 2: This part is used if the downstream device is a repeater 219.The repeater 219 authenticates with the devices connected to itsoutput(s) and passes the HDCP tree topology information up to the source104. The source 104 is the root and sinks/displays 106 are the leaves,while repeaters 219 make up the branches of the tree.

Part 3: The source 104 performs periodic checks with the sink/display106 to ensure that encryption is in sync. HDCP also supports a keyrevocation mechanism that is designed to prevent content from beingtransmitted to known hacked devices. If any part of authentication failsor any revoked devices are found in the HDCP tree, the transmitter 212must stop sending protected content and authentication starts over atPart 1. Authentication, encryption, and revocation are described indetail in the following sections.

Authentication Part 1

Part 1 of authentication is a key exchange protocol. The transmitter 212and receiver 216 calculate a common secret session key 108 to be usedfor encryption. If they cannot come up with the same key value,authentication fails and the receiver 216 will not be able to decryptthe content 202. The session key 108 is derived from each device'sprivate key according to the following protocol:

First the transmitter 212 generates a random number “An” and sends it tothe receiver 216. This value will be used later in the protocol. Thedevices 104, 106 then exchange KSVs. The receiver 216 also sends itsREPEATER bit, a flag that indicates whether or not it is part of arepeater. Now each device 104, 106 has the other device's Key SelectionVector (KSV). Each device 104, 106 uses the other device's Key SelectionVector to select twenty of its own keys. The forty bits in the KSVcorrespond to the indexes of each of the forty private keys. For everyset bit in the received KSV, the local private key at that index isselected. All KSVs have twenty set bits, so twenty keys are selected.The devices 104, 106 then each add up their selected keys to come upwith the sums Km and Km′, for the transmitter and receiver, respectively212, 216. For authentication to succeed, Km and Km′ must match. Eachdevice 104, 106 tells the other which of its own unique, secret keys toselect, and they both come up with the same sum. That may seemcounter-intuitive, but it is the aforementioned mathematicalrelationship between the keys and the KSVs that accounts for thisbehavior. The source 104 must determine whether Km and Km′ match.However, they are secret values, so they cannot be transmitted over theinterface cable or physical connection 102 for the DDC. Each device104,106 feeds Km (or Km′), the random number “An”, and the REPEATER bitinto their respective HDCP cipher engines in order for the transmitter212 to verify that the values match without sending them across thecable 102 for everyone to see. The resulting data stream is split intothree values:

R0/R0′: This return value may be shared between the devices 104, 106 andis used to verify that authentication was successful.

Ks/Ks′: This value is kept private and is used as the encryption sessionkey for the HDCP cipher.

M0/M: This value is also kept private and is used in Part 2 ofauthentication (if the downstream device is a repeater 219).

The receiver sends R0′ to the transmitter 212, which compares it againstits' own R0 value. If they match, that proves that the sums Km and Km′matched, and authentication is successful. Furthermore, the session keysKs and K match, so the receiver 214 will be able to decrypt the contentencrypted by the transmitter. If Part 1 of authentication wassuccessful, the transmitter 212 may begin sending encrypted content 202.If the downstream device is a repeater 219, the repeater 219 mustauthenticate with its own downstream device according to the sameprotocol. The transmitter 212 then starts a 5-second timer to allow forthe repeater 219 to perform Part 2 of authentication. If Part 2 fails ortimes out, authentication fails and the transmitter 212 must stoptransmitting the protected content 202.

Authentication Part 2

Part 2 of authentication only occurs if the downstream device is arepeater 219. The purpose of Part 2 is to inform the source 104 of alldownstream devices and the HDCP tree depth. The source 104 uses thisinformation to ensure that the tree topology maximums have not beenexceeded and to ensure that none of the downstream devices have beenrevoked by DCP. The repeater 219 first assembles a list of the KSVs ofall downstream devices, as well as the device count and the tree depth.The repeater 219 then passes this information up to the source 104. Toensure that this information hasn't been tampered with duringtransmission, each device takes this list, appends its secret valueM0/M0′ from Part 1, and calculates a SHA-1 hash of the whole thing. Thetransmitter 212 reads the hash result from the receiver 214 and comparesit against its own. If they match, Part 2 of authentication issuccessful.

Authentication Part 3

All HDCP devices are considered authenticated after successfulcompletion of Authentication Parts 1 and 2. Part 3 is simply a linkintegrity check to ensure that encryption is in sync between alltransmitter/receiver pairs 212, 214, 215, 216 in the tree. To supportlink integrity checks, the return values Ri and Ri′ roll over to a newvalue every 128 frames. Recall that the initial Ri values R0 and R0′were generated during Part 1 of authentication. Every two seconds, thetransmitter 212 compares the receiver's 216 Ri′ value against its own Rivalue to see if they match. If they do not, encryption is out of syncand the receiver 216 cannot correctly decrypt the content 202. The userwill see a scrambled or “snowy” image on the screen. In this case thetransmitter 212 must restart authentication from the beginning.

Encryption

The transmitter 212 uses the HDCP cipher engine to encrypt the content202. The session key Ks from Authentication Part 1 is used as the seedvalue, and the cipher output stream is simply XORed with the audiovisualcontent. The transmitter 212 then sends the XOR output to the receiver216 as the encrypted data stream. To decrypt the data, the HDCP receiver214 seeds its own cipher engine with its matching value Ks′. Since Ksequals Ks′, the cipher output matches that of the transmitter 212. Thereceiver 216 then XORs its cipher output stream with the encrypted data,and the output is the decrypted audiovisual content 202.

Revocation

The HDCP designers recognized that despite their best efforts, privatedevice keys could possibly be compromised. If such a compromise werediscovered, the designers wanted a method by which they could preventcontent from being sent to the compromised units. To this end, HDCPsources 104 are required to manage System Renewability Messages (SRMs).SRMs carry a list of revoked KSVs that may be provided with theaudiovisual content. For instance, a SRM could be stored on an HD-DVD ormay be transmitted with a cable television signal. If presented with anSRM, the HDCP source must check all the downstream KSVs obtained duringParts 1 and 2 against the KSVs listed in the SRM. If there are anymatches, the HDCP source must stop transmitting the protected content.SRMs are only supported by the HDCP source 104; neither repeaters 219nor sink/displays 106 handle SRMs.

HDCP eliminates the possibility of intercepting digital data midstreambetween the source 104 to the sink/display 106 because of theauthentication process as described above. However, in some situationwhen the source 104 and the sink/display 106 are HDCP compliant,non-HDCP content cannot be recorded and shared. This is an issue, forexample, in a university setting where instructors want students to havethe ability to copy and share non-HDCP content. More specifically, theuse of laptops during a university lecture by instructors and studentshas become common, particularly when wireless networks allow free campusinternet access. The instructors may show a PowerPoint presentation ofthe lecture and want students to view, record, and/or copy thepresentation. Additionally, some university professors are aware of theneeds of disabled students who require laptops to take notes and/or copythe presentation.

With HDCP compliant source 104 and sink/display 106 devices, studentswill not be able to copy and/or record presentation. As will beexplained below, the present invention discloses system, apparatus andmethod for allowing the non-copy protected content to be recorded and/orshared when the source 104 (that is HDCP compliant) and a sink/display106 (that is HDCP compliant or not). The present invention disclosesthat the source 104 does not recognize the sink/display 106 to be HDCPcompliant when the sink/display 106 itself is HDCP compliant. As aresult, the authentication process never occurs and hence failure ofauthentication is not possible. The HDCP compliant source 104 proceedsto transmit the non-HDCP content to the HDCP compliant sink/display 106even though the sink/display 166 is HDCP compliant.

FIG. 3 is a system 300 for enabling and disabling a DDC access toenable/disable a security protocol such as HDCP between a source 104(that is HDCP compliant) and sink/display 106 (that is HDCP compliant).The owner of the non-copy protected content may use the system 300 toenable or disable the DDC at the source 104 (that is HDCP compliant) andtransmit the non-copy protected content to the sink/display 106 (that isHDCP compliant or not). Thereby, enabling the viewers such as universitystudents to be able to record and/or copy the lecture. The system 300includes at least one source 104 a, 104 b, . . . , 104 n (collectively104) and at least one sink or display 106 a, 106 b, . . . , 106 n(collectively 106). Each source 104 includes an HDCP supported HDMItransmitter 212 configured to transmit audiovisual data to the at leastone sink 106. Each source 104 further includes a graphic generator (notshown) to generate the graphic or image. The HDCP transmitter 212receives the HDCP content 202 from an upstream content control function210.

Some sinks/displays 106 a may include an HDCP compliant receiver. Othersinks/displays 106 b may not include an HDCP compliant receiver. Thesource 104 determines via the authentication process what content can beviewed, recorded, and shared based on sinks/displays 106 that supportHDCP and sinks/displays 106 that do not support HDCP. The output of thesource 104 is connected to an input of a switcher device 302 through itsHDCP-protected interfaces. It should be understood that the switcherdevice 302 could be any device or apparatus that is capable of enabling,connecting, disabling, disconnecting an I2C signal used in DDCcommunication such as a relay, FET switch, I2C buffer, mux, and digitallogic.

The output of the switcher device 302 is connected to the input of thesink/display 106 via another interface 102 b. The interface 102 a, 102 bfor the input and the output of the switcher device 302 may be an HDMIcable that carries a variety of signals such as Transition MinimizedDifferential Signaling (TMDS), Digital Display Channel (DDC), Hot PlugDetect (HPD), and 5-volt.

When an HDCP source 104 (more specifically source 104 a) detects an HPDsignal from an HDCP compliant sink/display 106 (more specificallysink/display 106 a), the source 104 a will transmit the HDCP content 202to the sink/display 106 a after the authentication process issuccessful.

The audiovisual data 202 is encoded into three data channels. Thesechannels and a TMDS clock are carried over four differential pairs fromthe source 104 to the sink/display 106. The DDC is a communicationsinterface similar to I2C. This interface provides two-way communicationin a master-slave relationship. The upstream device 104 is the DDCmaster and the downstream device 106 is the DDC slave. The sink/display106 indicates its presence to the source 104 with the HPD signal. Thesink/display 106 can toggle the HPD signal to reset the HDMI connection(and thus, the HDCP session). Though not specifically defined by HDMI,many devices support a feature known as RxSense. There is no RxSensewire, but rather, sources 104 can detect that a sink/display 106 hasterminated the TMDS differential pairs. Similarly to HPD, this signalcan be used to detect the presence of a sink/display 106. The HDCPtransmitter 212 is the HDCP Device most upstream, and receives the HDCPcontent 202 from an upstream content control function 210.

The switcher device 302 is a fully modular and expandable matrixswitcher offering low-latency digital video and audio switching, and HDlossless multi-room signal distribution, for all types of A/V sources.The switcher device 302 may be a CRESTRON DIGITAL MEDIA SWITCHERavailable from Crestron Electronics, Inc. of Rockleigh, N.J. TheCRESTRON DIGITAL MEDIA SWITCHER is a field-configurable to handle, butnot limited to, 8, 16, or 32 audiovisual sources of virtually any type.The outputs are also field-configurable to provide, but not limited to,8, 16, or 32 room outputs and/or HDMI outputs in a single chassis. Theswitcher device 302 includes a multiplexer 306 coupled in-between the atleast one input card 308 a, 308 b, 308 n (collectively 308) and at leastone output card 310 a, 310 b, 310 n (collectively 310).

The multiplexer 306 transmits an audiovisual data signal 202 from the atleast one input card 308 to a first and at least a second output card310. The multiplexer 306 dynamically switches between the first and atleast second output cards 310 a, 310 b based on a user control signal316 that activates one of the at least one sinks/displays 106. Each ofthe output cards 310 is coupled to the at least one sink/display 106 viainterface cable/physical connection 102 b. The switcher 302 furtherincludes a processing unit 318 coupled to the multiplexer 306. Theprocessing unit 318 includes at least one transceiver 320 forbidirectional communications with user interface devices (e.g., 323,324), in part, to receive the user control signal 316 and event signal314. The user interface device 323, 324 transmits the user controlsignal 316 from a touch panel display 324 via a control system 322. Anend user may also transmit the user control signal 316 from a wirelessdevice 323. Software tools 328 may be loaded onto the wireless deviceand/or touch panel 324 to assist the end user in selecting a desiredsink/display 106. In response to the user activating the desired sink ordisplay 106, the end user device transmits the user control signal 316to the switcher 302. A user interface device 324 may be a display devicesuch as, but not limited to, a graphical user interface (GUI) touchpanel, mobile device 323, tablet, projector, desktop computer, andlaptop.

FIG. 4 is a schematic of an input card 308 in accordance with anillustrative embodiment of the present invention. The input card 308includes a switch 332 connected in series with an integrated circuit326. The switch 332 may be, but is not limited to, a mechanical switch,electrically operated switch, solid state relay, latching relay, reedrelay, Single Pole Single Throw (SPST) relay, Single Pole Double Throw(SPDT) relay, Double Pole Single Throw (DPST) relay or Double PoleDouble Throw (DPDT) relay. The interface cable 102 a is connected to theinput card 308. Various signals are carried in the interface cable 102 aincluding TMDS, DDC, HPD, and five (5) volts signals. The switch 332 andintegrated circuit 326 are in series, which in turn, is in parallel withan Extended Display Identification Data (EDID) memory 330. The inputcard 308 includes an integrated circuit 326 that includes a securityprotocol enabled receiver 214. The security protocol may be HDCP. Inoperation, the input card 308 detects the presence of an event signal304 from the user interface devices (e.g., 323, 324). In response to thedetection of the event signal 304, the switch 332, 532, 632 switchesdynamically to a closed position for enabling the at least one source104 to authenticate with the input card 308, 508, 608, 708 and enablingthe output card 310 to authenticate with the at least one sink 106 forsecurity protocol encryption.

In response to the non-detection of the event signal 304, the switch332, 532, 632 switches dynamically to an open position in order todisable the at least one source 104 from initiating an authenticationwith the input card 308, 508, 608, 708. Therefore, the output card 310also does not attempt to initiate an authentication with the at leastone sink 106 for security protocol encryption. Since the source 104 doesnot detect the HDCP capability of the input card 308, 508, 608, 708,authentication never occurs or more specifically an attempt toauthenticate never happened, therefore a failed authentication neveroccurred.

More specifically, when the source 104 fails authentication or changesthe resolution of the multimedia data or changes the resolution of thesink 106, the reestablishment and encoding/decoding of the HDCP becomeunstable, such that the sink 106 cannot display the multimedia datanormally. The source 104 uses a hot-plug detect signal of the HDMIinterface to identify the coupling state between the sink 106 and thesource 104. When the hot-plug detect signal is a logic high level pulsesignal, the source 104 and the sink 106 are in a coupled state. In theconventional art, in order to solve the problem that the sink does notfunction normally, it may be required to disconnect and connect the HDMIconnector again or restart the source 104 to enable the source 104 toread the EDID again and reestablish the HDCP.

Continuing on to the operation, typically, the source 104 initiallyauthenticates with the input card 308, 508, 608, 708. Once thatauthentication is successful, the output card 310 then authenticateswith the sink 106. In one embodiment, when the input card 308 does notdetect the event signal 304, the switch 332, 532, 632 switchesdynamically to an open position in order to disable the source 104 frominitiating authentication with the input card 308, 508, 608, 708. As aresult, the output card 310 also does not attempt to initiate anauthentication with sink 106 for security protocol encryption. Thenon-copy protected content is still transmitted to the sink/display 106even though the source 104 and the sink/display 106 are HDCP compliant.Moreover, the end user can copy and/or share the non-copy protectedcontent. Without, in part, the switch 332 and its placement thereof, thenon-copy protected content will not be able to be shared and/or recordedwhen the source 104 and the sink/display 106 are HDCP compliant.

Typically, if an end user wants to switch between watching copyprotected content (HDCP required) or watching/recording non-copyprotected content such as a PowerPoint in a lecture scenario, the enduser installs two different AV distribution switcher infrastructure. OneAV switcher supports HDCP and another AV switcher does not support HDCP.When the customer wants to watch copy protected content, the end userphysically plugs into the HDCP supported AV switcher and when the enduser wants to watch/record lectures, the end user plugs into a differentsystem. The present disclosure allows a single A/V switcher system to beused so that the end user does not need to physically change the cablepositioning. Moreover, the present disclosure saves resources andcomplexities because separate systems do not need to be setup.

It should be understood that there may be more than one source 104 andsink/display 106 connected to the system 300. It should also beunderstood that there may be more than one input card 308 a, 308 b, 308n (collectively 308) with similar electrical connections and physicallayouts.

FIG. 5 is a schematic of an input card 508 in accordance with anotherillustrative embodiment of the present invention. The input card 508 hasthe DDC signal in the interface cable 102 a into the input card 508. Theinput card 508 includes an integrated circuit 526. The integratedcircuit 526 includes a switch 532, a security protocol enabled receiver514, and an EDID 530. The EDID 530 and receiver 514 are in parallel witheach other. The EDID 530 and receiver 514, in turn, are in series withthe switch 532. The switch 532, security protocol enabled receiver 514,and EDID 530 have full integration on the integrated circuit 526. Whenthe input card 508 does not detect the event signal 304 from the userinterface device 323, 324, the switch 532 dynamically switches to anopen or disconnect position. The non-copy protected content is displayedon the sink/display 106. And the non-copy protected content can berecorded and/or shared even when the sink/display 106 is HDCP compliant.The EDID 535 is connected to the interface cable 102 a prior to thecable 102 a inputting into the switch 532. In one embodiment, the EDID535 is connected externally to the integrated circuit 526. The internalEDID 530 is then disabled via software. When the input card 508 detectsthe event signal 304 from at least one user interface device (323, 324),the switch 532 dynamically switches to a closed or connect position andthe non-copy protected content or HDCP content 202 is transmitted to thesink/display 106. Both the non-copy protected content and the HDCPcontent 202 cannot be recorded and/or shared when the sink/display 106is HDCP compliant.

FIG. 6 is a schematic of an input card 608 in accordance with yetanother illustrative embodiment of the present invention. The input card608 is similar to the input card 508 with the exception that there is noexternal EDID 535 and the connection to the switch 632. Input card 608has the DDC signal on the interface cable 102 a, which connects to theinput card 608. The input card 608 includes an integrated circuit 626.The integrated circuit 626 includes a switch 632, a security protocolenabled receiver 614, and an EDID 630. The switch 632 is in series withthe receiver 614, which in turn, is in parallel with the EDID 630. Theswitch 632, security protocol enabled receiver 614, and EDID 630 havefull integration on the integrated circuit 626. The EDID 630 isconnected to line 102 a before it is connected into the input of theswitch 632. That way, when the switch 632 is disconnected, non-copyprotected content can still be passed to the sink/display 106. Hence,non-copy protected content can be recorded and/or stored even whensink/display 106 is HDCP compliant. As described above, when the inputcard 608 does not detect the event signal 304, the switch dynamicallyswitches to an open or disconnect position in order to disable the atleast one source 104 from being able to detect the HDCP capability ofthe input card 608. As a result, the output card 310 also does notattempt to authenticate with the sink 106.

FIG. 7 is a schematic of an input card 708 in accordance with yetanother illustrative embodiment of the present invention. Thisembodiment changes the register of the security protocol enabledreceiver 714. According to the HDCP specification, the register ormemory location of the receiver 714 is typically 0x70. By using asoftware program, the register memory location is changed to, forexample, 0x60. As a result, the source 104 will not recognize thereceiver 714. Since the receiver 714 is not recognized, theauthentication process never gets initiated and hence no failure inauthentication is possible. Non-copy protected content can still bepassed to the sink/display 106 even though the sink/display 106 is HDCPcompliant. The non-copy protected content can be recorded and/or shared.

The following is a pseudo-code representation of the operation inaccordance with an illustrative embodiment of the present invention.

User sets HDCP enable or disable for a desired sink/display

Drop hot plug to change HDCP switch

Wait until hot plug signal goes away based on measurements such as syncmeasurements and sync detect.

Perform switch method

Set hardware disconnect switch

Raise hot plug

FIG. 8 illustrates a method 800 for enabling/disabling DDC access toenable/disable HDCP according to an embodiment of the invention.Procedure 800 begins at step 805. In step 810 a system (e.g., 300) orapparatus (e.g., 308, 408, 508, 608, 708) detects a user control signal316 to activate one of the at least one sinks 106. If the system (e.g.,300) or apparatus (e.g., 308, 408, 508, 608, 708) does not detect theuser control signal 316, the procedure goes back to step 805. However,if there is a detection of the user control signal 316, the system(e.g., 300) or apparatus (e.g., 308, 408, 508, 608, 708) activates orenables the at least one sink 106 for receiving and displayingaudiovisual signal, which is the HDCP content 202 in step 815.

In step 820, the system (e.g., 300) or apparatus (e.g., 308, 408, 508,608, 708) detects an event signal 304 from at least one user interfacedevice (323, 324). In response to the detection of the event signal 304,the switch 332 switches dynamically to a closed position for enablingthe at least one source 104 to authenticate with the input card 308,508, 608, 708 and enabling the output card 310 to authenticate with theat least one sink 106 for security protocol encryption in step 850. Thesystem (e.g., 300) or apparatus (e.g., 308, 408, 508, 608, 708) permitsthe transmission of audiovisual signal or HDCP content 202 from the atleast one source 104 to the enabled at least one sink 106 uponsuccessful authentication between the at least one source 104 and theactivated at least one sink 106 in step 855. In step 860, the system(e.g., 300) or apparatus (e.g., 308, 408, 508, 608, 708) disablescontrol of the enabled at least one sink 106 from being able to recordthe audiovisual signal that contains copy protected content (e.g., HDCPcontent 202) from being able to be recorded and shared.

In response to the system (e.g., 300) or apparatus (e.g., 308, 408, 508,608, 708) not detecting the event signal 304, the switch 332 switchesdynamically to an open position in order to disable the at least onesource 104 from initiating an authentication with the input card 308,508, 608, 708 in step 825. To this end, the output card 310 also doesnot attempt to initiate an authentication with the at least one sink 106for security protocol encryption. In step 830, the system (e.g., 300) orapparatus (e.g., 308, 408, 508, 608, 708) permits transmission of theaudiovisual signal (e.g., HDCP content 204) to be displayed from the atleast one source 104 onto the activated at least one sink 106. In step835, the system (e.g., 300) or apparatus (e.g., 308, 408, 508, 608, 708)enables control of the enabled at least one sink 106 from being able torecord since the audiovisual signal 202 contains non-copy protectedcontent.

Any process descriptions or blocks in flow charts should be understoodas representing modules, segments, or portions of code that include oneor more executable instructions for implementing specific logicalfunctions or steps in the process. Alternate implementations areincluded within the scope of the preferred embodiment of the presentinvention in which functions may be executed out of order from thatshown or discussed, including substantial concurrence or reverse order,depending on the functionality involved, as would be understood by thosereasonably skilled in the art of the present invention. Also, stepsdisclosed as separate may be performed concurrently or combined, and astep shown as discrete may be performed as two or more steps.Furthermore, numerical values and disclosures of specific hardware areillustrative rather than limiting. Moreover, while the preferredembodiment has been disclosed in the context of DVI, the invention canbe implemented for use with another suitable interface that uses HDCP,such as HDMI or any substantially DVI-like interference. Therefore, thepresent invention should be construed as limited only by the appendedclaims.

INDUSTRIAL APPLICABILITY

To solve the aforementioned problems, the present invention is a uniquemethod, apparatus, and system for enabling and/or disabling dynamicDisplay Identification Data to enable and/or disable High-BandwidthDigital Content Protection without an authentication process.

LIST OF ACRONYMS USED IN THE DETAILED DESCRIPTION OF THE INVENTION

The following is a list of the acronyms used in the specification inalphabetical order.

-   -   API Application Programming Interface    -   AV Audiovisual    -   CD ROM Compact Disk Read-Only Memory    -   CPU Central Processing Unit    -   CSS Content Scrambling System    -   DCP Digital Content Protection, LLC.    -   DDC Digital Display Channel    -   DDWG Digital Display Working Group    -   DLI Digital Light Interface    -   DP DisplayPort    -   DPDT Double Pole Double Throw relay    -   DPST Double Pole Single Throw relay    -   DRM Digital rights management    -   DVD Digital Versatile Disk    -   DVI Digital Video Interface    -   EDID Extended Display Identification Data    -   GVIF Giga-bit Video Interface    -   GUI Graphical User Interface    -   HDCP High-Bandwidth Digital Content Protection    -   HD-DVD High-Definition Digital Versatile/Video Disc    -   HDMI High-Definition Multimedia Interface    -   HP Hot Plug Detect    -   IP Internet Protocol    -   KSV Key Selection Vector    -   RAM Random Access Memory    -   ROM Read Only Memory    -   SDK Software Development Kit    -   SPDT Single Pole Double Throw relay    -   SPST Single Pole Single Throw relay    -   SRM System Renewability Message    -   TCP/IP Transmission Control Protocol/Internet Protocol    -   TMDS Transition Minimized Differential Signaling    -   TV Television    -   UDI Unified Display Interface    -   USB Universal Serial Bus    -   WHDI Wireless Home Digital Interface

ALTERNATE EMBODIMENTS

It is to be understood that both the general and detailed descriptionsabove are exemplary and explanatory only and are not restrictive of theinvention. It should be understood that the invention can be implementedin a DVI or HDMI capable set-top box. While the invention has beendisclosed for use with HDCP, it can be used with any other securityprotocol that satisfies the following two attributes. The firstattribute is that the security protocol is tied to the video contentbeing transmitted; that is, if the video attributes change, the securityprotocol must be renegotiated. The second attribute is that the securityprotocol offers a way to determine or detect whether the remote deviceis capable of supporting the security protocol.

At least a portion of the input card (e.g., 308, 408, 508, 608, 708) ofthe present invention may be implemented in an integrated circuit. Informing integrated circuits, a plurality of identical die is typicallyfabricated in a repeated pattern on a surface of a semiconductor wafer.Each die includes a device described herein, and may include otherstructures and/or circuits. The individual die are cut or diced from thewafer, then packaged as an integrated circuit. One skilled in the artwould know how to dice wafers and package die to produce integratedcircuits. Integrated circuits so manufactured are considered part ofthis invention.

In this description, various functions and operations may be describedas being performed by or caused by software code to simplifydescription. However, those skilled in the art will recognize what ismeant by such expressions is that the functions result from execution ofthe code by a processor, such as a microprocessor. Alternatively, or incombination, the functions and operations can be implemented usingspecial purpose circuitry, with or without software instructions, suchas using Application-Specific Integrated Circuit (ASIC) orField-Programmable Gate Array (FPGA). Embodiments can be implementedusing hardwired circuitry without software instructions, or incombination with software instructions. Thus, the techniques are limitedneither to any specific combination of hardware circuitry and software,nor to any particular source for the instructions executed by the dataprocessing system.

While some embodiments can be implemented in fully functioning computersand computer systems, various embodiments are capable of beingdistributed as a computing product in a variety of forms and are capableof being applied regardless of the particular type of machine orcomputer-readable media used to actually effect the distribution.

At least some aspects disclosed can be embodied, at least in part, insoftware. That is, the techniques may be carried out in a computersystem or other data processing system in response to its processor,such as a microprocessor, executing sequences of instructions containedin a memory, such as ROM, volatile RAM, non-volatile memory, cache or aremote storage device.

Routines executed to implement the embodiments may be implemented aspart of an operating system, middleware, service delivery platform, SDK(Software Development Kit) component, web services, or other specificapplication, component, program, object, module or sequence ofinstructions referred to as “computer programs.” Invocation interfacesto these routines can be exposed to a software development community asan API (Application Programming Interface). The computer programstypically comprise one or more instructions set at various times invarious memory and storage devices in a computer, and that, when readand executed by one or more processors in a computer, cause the computerto perform operations necessary to execute elements involving thevarious aspects.

A machine readable medium can be used to store software and data whichwhen executed by a data processing system causes the system to performvarious methods. The executable software and data may be stored invarious places including for example ROM, volatile RAM, non-volatilememory and/or cache. Portions of this software and/or data may be storedin any one of these storage devices. Further, the data and instructionscan be obtained from centralized servers or peer to peer networks.Different portions of the data and instructions can be obtained fromdifferent centralized servers and/or peer to peer networks at differenttimes and in different communication sessions or in a same communicationsession. The data and instructions can be obtained in their entiretyprior to the execution of the applications. Alternatively, portions ofthe data and instructions can be obtained dynamically, just in time,when needed for execution. Thus, it is not required that the data andinstructions be on a machine readable medium in entirety at a particularinstance of time.

Examples of computer-readable media include but are not limited torecordable and non-recordable type media such as volatile andnon-volatile memory devices, read only memory (ROM), random accessmemory (RAM), flash memory devices, floppy and other removable disks,magnetic disk storage media, optical storage media (e.g., Compact DiskRead-Only Memory (CD ROMS), Digital Versatile Disks (DVDs), etc.), amongothers. The instructions may be embodied in digital and analogcommunication links for electrical, optical, acoustical or other formsof propagated signals, such as carrier waves, infrared signals, digitalsignals, etc.

In general, a machine readable medium includes any mechanism thatprovides (i.e., stores and/or transmits) information in a formaccessible by a machine (e.g., a computer, network device, personaldigital assistant, manufacturing tool, any device with a set of one ormore processors, etc.).

In various embodiments, hardwired circuitry may be used in combinationwith software instructions to implement the techniques. Thus, thetechniques are neither limited to any specific combination of hardwarecircuitry and software nor to any particular source for the instructionsexecuted by the data processing system.

Although some of the drawings illustrate a number of operations in aparticular order, operations which are not order dependent may bereordered and other operations may be combined or broken out. While somereordering or other groupings are specifically mentioned, others will beapparent to those of ordinary skill in the art and so do not present anexhaustive list of alternatives. Moreover, it should be recognized thatthe stages could be implemented in hardware, firmware, software or anycombination thereof.

Although illustrative embodiments of the present invention have beendescribed herein with reference to the accompanying drawings, it is tobe understood that the invention is not limited to those preciseembodiments, and that various other changes and modifications may bemade therein by one skilled in the art without departing from the scopeof the appended claims.

What is claimed is:
 1. A system for enabling/disabling Display DataChannel (DDC) access to enable/disable a security protocol, the systemcomprising: at least one source (104); at least one sink (106); and aswitcher device (302) communicatively coupled in-between the at leastone source and the at least one sink, the switcher device comprises: amultiplexer (306) coupled in-between at least one input (308, 508, 608,708) and output cards (310) and configured to transmit an audiovisualsignal (202) from the at least one input card to a first and at least asecond output card (310 a, 310 b) via a physical connection (102);wherein the multiplexer is configured to dynamically switch between thefirst and at least second output card based on a user control signal(316) that activates one of the at least one sinks, wherein each of theoutput cards is coupled to the at least one sink; wherein the input cardcomprises: an integrated circuit (326, 526, 626, 726) that includes asecurity protocol enabled receiver (214, 216, 514, 614, 714); and aswitch (332, 532, 632) coupled in-between the security protocol enabledreceiver and an Extended Display Identification Data (EDID) memory (330,530, 630, 730), wherein the input card is configured to detect thepresence of an event signal (304) from at least one user interfaceddevice (323, 324), wherein in response to the detection of the eventsignal, the switch is configured to dynamically switch to a closedposition in order to enable the at least one source configured toperform a first authentication with the input card and the output cardconfigured to perform a second authentication with the at least one sinkfor security protocol encryption, and wherein in response to thenon-detection of the event signal, the switch is configured todynamically switch to an open position in order to disable the at leastone source from initiating a first authentication with the input card,therefore the output card also does not attempt to initiate a secondauthentication with the at least one sink for security protocolencryption.
 2. The system of claim 1, wherein the security protocolcomprises High-Bandwidth Digital Content Protection (HDCP).
 3. Thesystem of claim 1, wherein the at least one source and sink areHigh-Bandwidth Digital Content Protection compliant.
 4. The system ofclaim 1, wherein the at least one physical connection interconnects tothe at least one source, the switcher device, and the at least one sinkdevice.
 5. The system of claim 1, wherein the physical connectioncomprises an HDMI cable that carries Transition Minimized DifferentialSignal (TMDS), Digital Display Channel (DDC), and Hot Plug Detect (HPD)signals.
 6. The system of claim 1, wherein the switch device is coupledin-between the integrated circuit and the EDID memory.
 7. The system ofclaim 1, wherein the integrated circuit comprises the HDCP enabledreceiver, EDID memory, and switch.
 8. The system of claim 7, wherein theintegrated circuit comprises the switch device, HDCP enabled receiver,and EDID memory, and wherein the switch device is coupled in-between theHDCP enabled receiver and the EDID memory.
 9. The system of claim 7,wherein the integrated circuit comprises the switch device, HDCP enabledreceiver, and EDID memory, wherein the HDCP enabled receiver and EDIDmemory are in parallel with respect to each other, and wherein thecombination of the HDCP enabled receiver and EDID memory are in serieswith the switch device.
 10. The system of claim 9, wherein theintegrated circuit is in parallel with another EDID memory (535). 11.The system of claim 1, wherein the switch device comprises a mechanicalswitch, electrically operated switch, solid state relay, latching relay,reed relay, Single Pole Single Throw (SPST) relay, Single Pole DoubleThrow (SPDT) relay, Double Pole Single Throw (DPST) relay, and DoublePole Double Throw (DPDT) relay.
 12. The system of claim 1, wherein theswitcher device further comprises a processor (318) coupled to atransceiver (320) for bidirectional communication with the at least oneuser interface device, wherein the processor and transceiver areconfigured to process and receive the user control signal in response toa user activating the at least one user interface device.
 13. The systemof claim 12, wherein the at least one user interface device comprises agraphical user interface (GUI) touch panel, mobile device, tablet, andcomputer.
 14. The system of claim 12, wherein the at least one userinterface device is configured to transmit the user control signal wiredor wirelessly.
 15. The system of claim 12, wherein the at least one userinterface device further comprises software tools (328) to assist theuser in selecting the at least one source.
 16. The system of claim 1,wherein the at least one source comprises a game console, digitalversatile disc (DVD) player, cable box, desktop computer, laptop, andblu-ray player.
 17. The system of claim 1, wherein the least one sinkcomprises a display device, wherein the display device is a television.18. The system of claim 1, wherein the input card is configured topermit the transmission of audiovisual signal from the at least onesource to the at least one sink upon successful authentication.
 19. Thesystem of claim 1, wherein the input card is configured to disable theat least one sink from being able to record since the audiovisual signalincludes copy protected content.
 20. The system of claim 1, wherein theinput card is configured to permit the transmission of audiovisualsignal from the at least one source to the at least one sink.
 21. Thesystem of claim 1, wherein the input card is configured to enable the atleast one sink from being able to record since the audiovisual signalincludes non-copy protected content.
 22. The system of claim 1, whereinthe second authentication is attempted if the first authentication issuccessful between the at least one source and the input card.
 23. Thesystem of claim 1, wherein the first and second authentications includesan encryption.
 24. A switcher device, comprising: a multiplexer (306)coupled in-between at least one input (308, 508, 608, 708) and outputcards (310) and configured to transmit an audiovisual data signal (202)from the at least one input card to a first and at least a second outputcard; wherein the multiplexer is configured to dynamically switchbetween the first and at least second output card (310 a, 310 b) basedon a user control signal (316) that activates one of at least one sinks(106); wherein each of the output cards is coupled to the at least onesink; wherein the input card comprises: an integrated circuit (326, 526,626, 726) that includes a High-Bandwidth Digital Content Protection(HDCP) enabled receiver; and a switch (332, 532, 632) coupled in-betweenthe HDCP enabled receiver and an Extended Display Identification Data(EDID) memory (330, 530, 630, 730), wherein the at least one input cardis configured to detect the presence of an event signal (304) from theat least one user interface device (323, 324); wherein in response tothe detection of the event signal, the switch is configured todynamically switch to a closed position in order to enable the at leastone source configured to authenticate with the input card and the outputcard configured to authenticate with the at least one sink for securityprotocol encryption, and wherein in response to the non-detection of theevent signal, the switch is configured to dynamically switch to an openposition in order to disable the at least one source from initiating anauthentication with the input card, therefore the output card also doesnot attempt to initiate an authentication with the at least one sink forsecurity protocol encryption.
 25. The switcher device of claim 24,wherein the switch device is coupled in-between the integrated circuitand the EDID memory.
 26. The switcher device of claim 24, wherein theintegrated circuit comprises the HDCP enabled receiver, EDID memory, andswitch.
 27. The switcher device of claim 26, wherein the integratedcircuit comprises the switch device, HDCP enabled receiver, and EDIDmemory, and wherein the switch device is coupled in-between the HDCPenabled receiver and the EDID memory.
 28. The switcher device of claim26, wherein the integrated circuit comprises the switch device, HDCPenabled receiver, and EDID memory, wherein the HDCP enabled receiver andEDID memory are in parallel with respect to each other, and wherein thecombination of the HDCP enabled receiver and EDID memory are in serieswith the switch device.
 29. The switcher device of claim 28, wherein theintegrated circuit is in parallel with another EDID memory (535). 30.The switcher device of claim 24, wherein the switch device comprises amechanical switch, electrically operated switch, solid state relay,latching relay, reed relay, Single Pole Single Throw (SPST) relay,Single Pole Double Throw (SPDT) relay, Double Pole Single Throw (DPST)relay, and Double Pole Double Throw (DPDT) relay.
 31. The switcherdevice of claim 24, further comprises a processor (318) coupled to atransceiver (320) for bidirectional communication with the at least oneuser interface device, wherein the processor and transceiver areconfigured to process and receive the user control signal in response toa user activating the user activating the at least one user interfacedevice.
 32. The switcher device of claim 24, wherein the at least oneuser interface device comprises at least one graphical user interface(GUI) touch panel, mobile device, tablet, and computer.
 33. The switcherdevice of claim 24, wherein the at least one user interface device isconfigured to transmit the user control signal wired or wirelessly. 34.The switcher device of claim 24, wherein the at least one user interfacedevice further comprises software tools (328) to assist the user inselecting the at least one source.
 35. The switcher device of claim 24,wherein the least one source comprises a game console, digital versatiledisc (DVD) player, cable box, desktop computer, laptop, and blu-rayplayer.
 36. The switcher device of claim 24, wherein the least one sinkcomprises a display device, wherein the display device is a television.37. A method for enabling/disabling Display Data Channel (DDC) access toenable/disable High-Bandwidth Digital Content Protection, the methodcomprising: detecting (step 810) a user control signal to activate oneof at least one sinks; in response to the detection of the user controlsignal, enabling (step 815) the selected at least one sink for receivingaudiovisual signal; detecting (step 820) an event signal; wherein inresponse to the detection of the event signal, switching the switchdynamically (step 850) to a closed position for enabling the at leastone source to authenticate with the input card and enabling the outputcard to authenticate with the at least one sink for security protocolencryption; permitting (step 855) the transmission of audiovisual signalfrom the at least one source to the enabled at least one sink uponsuccessful authentication; and disabling (step 860) control of theenabled at least one sink from being able to record since theaudiovisual signal contains copy protected content; wherein in responseto the non-detection of the event signal, switching the switchdynamically (step 825) to an open position in order to disable the atleast one source from initiating an authentication with the input card,therefore the output card also does not attempt to initiate anauthentication with the at least one sink for security protocolencryption; permitting (step 830) the transmission of the audiovisualsignal to be displayed from the at least one source to the enabled atleast one sink; and enabling (step 835) control of the enabled at leastone sink from being able to record since the audiovisual signal containsnon-copy protected content.
 38. The method of claim 37, wherein theevent signal is a signal that includes activating a particular mode ofthe at least one source, wherein the mode includes playing a blu-rayDVD, displaying a PowerPoint presentation, displaying a website,collaborating on a white board application, using a document camera, andstreaming content from a media player.
 39. The method of claim 38,wherein the mode is associated with the audiovisual signal containingeither copy protected content or non-copy protected content.
 40. Themethod of claim 37, wherein detecting the user control signal wired orwirelessly.
 41. The method of claim 37, wherein in response to detectingthe event signal, changing an address of an HDCP enabled receiver toanother address so that the at least one source does not detect the HDCPcompatibility of the input card.
 42. An integrated circuit, comprising:an enabled High-Bandwidth Digital Content Protection (HDCP) receiver(214, 216, 514, 614, 714); an Extended Display Identification Data(EDID) memory (330, 530, 630, 730); and a switch (332, 532, 632) coupledin-between the security protocol enabled receiver and the EDID memory,wherein the integrated circuit is configured to detect the presence ofan event signal (304) from at least one user interface device (323,324), wherein in response to the detection of the event signal, theswitch is configured to dynamically switch to a closed position in orderto enable the at least one source configured to authenticate with theinput card and the output card configured to authenticate with the atleast one sink for security protocol encryption, and wherein in responseto the non-detection of the event signal, the switch is configured todynamically switch to an open position in order to disable the at leastone source from initiating an authentication with the input card,therefore the output card also does not attempt to initiate anauthentication with the at least one sink for security protocolencryption.
 43. A computer program product for enabling and disabling asecurity protocol, the computer program product comprising: a computerreadable storage medium having computer readable program code embodiedtherewith, the computer readable program code comprising: computerreadable program code configured to: detect a user control signal toactivate one of at least one sinks; in response to the detection of theuser control signal, enabling the selected at least one sink forreceiving audiovisual signal; detect an event signal; wherein inresponse to the detection of the event signal, switching the switchdynamically to a closed position for enabling the at least one source toauthenticate with the input card and enabling the output card toauthenticate with the at least one sink for security protocolencryption; permit the transmission of audiovisual signal from the atleast one source to the enabled at least one sink upon successfulauthentication; and disable control of the enabled at least one sinkfrom being able to be recorded since the audiovisual signal containscopy protected content; wherein in response to the non-detection of theevent signal, switch the switch dynamically to an open position in orderto disable the at least one source from initiating an authenticationwith the input card, therefore the output card also does not attempt toinitiate an authentication with the at least one sink for securityprotocol encryption; permit the transmission of the audiovisual signalto be displayed from the at least one source to the enabled at least onesink; and enable (step 945) control of the enabled at least one sinkfrom being able to record since the audiovisual signal contains non-copyprotected content.
 44. The computer program product of claim 43, whereindetecting the user control signal wired or wirelessly.
 45. The computerprogram product of claim 43, further comprising in response to detectingthe event signal, changing an address of an HDCP enabled receiver toanother address so that the at least one source does not detect the HDCPcompatibility of the input card.